Block Editor: Include the fixes targetted for WordPress 5.8 RC3.

This includes the following fixes:
 - Safari: see if compositing layer size is more reasonable when position fixed divs are not inserted into content.
 - Site Logo Block: update Site Logo block UI and option syncing.
 - Fix moving inner blocks in the Widgets Customizer.
 - Allow themes to provide empty values for color.duotone and spacing.units
 - Update getTermsInfo() to workaround parsing issue for translatable strings.
 - Specify what settings can be part of settings.layout.
 - Update conditions to hide duotone panel.
 - Prevent entering invalid values in the Query Loop block config.
 - Prevent color panel from showing as empty.
 - Avoid calling gutenberg_ functions within code shipped through WordPress Core.

Props desrosj.
See #53397.


git-svn-id: https://develop.svn.wordpress.org/trunk@51421 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/theme.json

@@ -3,7 +3,9 @@
 	"settings": {
 		"color": {
 			"custom": true,
-			"customGradient": true,
+			"customDuotone": true,
+ 			"customGradient": true,
+ 			"link": false,
 			"duotone": [
 				{
 					"name":  "Dark grayscale" ,
@@ -108,7 +110,6 @@
 					"slug": "midnight"
 				}
 			],
-			"link": false,
 			"palette": [
 				{
 					"name": "Black",